En el mes de Mayo tendremos una interesantísima sesión doble:
Tendremos el gran privilegio de recibir a Heather VanCura, la presidenta del Java Community Process Program (JCP Program), para lo que probablemente sea una de las charlas más enfocadas en Java y la comunidad del JUG.
Será una oportunidad ideal para conocer y hablar de Java y de la plataforma y cómo la comunidad (y tú como miembro de ella) puedes contribuir y participar en su futuro.
Por otro lado, coincide también en Madrid en esta fecha Sven Ruppert, Developer Advocate de @Vaadin y uno de los Groundbreakers, que nos hablará de "Functional Reactive with Core Java"
Os dejamos la descripción de la charlas y de la bio de Heather:
# How to Participate in the Future of Java
This session will explore how Java development has been brought into the open and many of the shifts in the Java community over the past year, Several Java developer efforts have brought open source development processes and new levels of transparency and participation into their communities. Learn about the latest Java innovations to the Java SE Platform - Java SE 10, 11, 12 and beyond. Since the initiation of efforts to expand the developer participation in the Java community, Java standards development is more open that it ever has been. Learn how to take part in the Java developer community and the upcoming changes to Java - you can participate as an individual, corporation, or nonprofit such as a Java user group (JUG). This session answers questions about why and how to participate in the evolution of the Java platform. You will also learn about the global Adoption programs and how you can participate in contributing to the future of Java.
## Heather VanCura
### Director and Chairperson of the JCP Program
Heather VanCura is the Director and Chairperson of the JCP Program. In her role she is responsible for the chairing the Executive Committee, and providing overall leadership of the community. Heather oversees the JCP.org web site, JSR management, community building, events, marketing, communications, and growth of the membership. She is also a contributor and leader of the community driven Adopt-a-JSR programs. In 2014, Heather became Spec Lead for the ongoing JCP.Next efforts through JSR 364 and JSR 387. Heather is passionate about Java and developer communities. She enjoys trying new sports and fitness activities in her free time.
# Functional Reactive with Core Java
There are a lot of reactive frameworks in the field, some with functional languages for the JVM. However, Java gives you both. But how you could combine this and use this without adding the next big framework to your project? We will have a Core Java journey to explore a lot of excellent possibilities based on the JDK.
## Sven Ruppert
Java coder since 1996, Oracle @groundbreakers, Developer Advocate
@Vaadin and Speaker, Helping developers world-wide to grow their business.

Java has been crucial for the worldwide web. Some would argue it is at the heart of it along with HTML and CSS. The programming language that is traditional and useful in creating highly interactive webpages, it is also now useful in making simple or advanced smart contracts and it is number 2 after C++ for most of the rankings also for blockchains.
Most existing blockchain smart contract frameworks use their own DSL and proprietary tools making them much less accessible for developers and thus locking anyone who develops solutions on top of them into an esoteric tool chain.
In this lecture we will present a blockchain contracts framework developed in pure Java and deployed into standard Java JRE.
The talk will cover the topics:
- Quick intro to blockchain primitives:
- Transactions
- Blocks
- Miners
- Consensus
- proof of work
- proof of stake
- smart contracts
We will then deep dive into existing challenges to blockchain contracts design
- Stateful contracts
- Metering contract execution
- Smart contracts security concerns
Next we review how our Java based lightweight contracts framework solves these challenges
- Stateless contracts support parallelism
- Custom class loaders for securely storing and loading blockchain contracts
- Utilizing the Java security model for sandbox execution of contracts
- Verification of deployed contracts against the contract original source code
- Verification of contract execution using multi-signature accounts
- Oracle (of delphi) contracts
And finally demo the technology and discuss some real-world use cases
- Sample smart contract
- Unit test a smart contract
- Smart contract deployment and execution
- Use cases

Recibimos la visita de otro JUG leader, en esta ocasión Mary Grygleski desde Chicago Java Users Group (CJUG). Con una amplia experiencia trabajando en sistemas reactivos, nos hablará de la construcción de sistemas reactivos con Java.
## About this talk.
As Java is an object-oriented language that inherently supports the imperative programming style, asynchronicity presents a challenge that can turn the code into nightmare. One way to deal with the complexity of asynchronicity is to introduce reactivity onto the coding level (reactive programming), and/or to handle it on the design and architecture level (reactive systems design).
This talk presents to the audience a few of the major Java-based reactive frameworks and toolkits in the market today, such as RxJava, Spring Reactor, Akka, and Vet.x. It will start by going over the basic tenets of reactive systems, and some examples of the problems that these systems aim to solve. It will discuss the 2 most commonly used Java frameworks for implementing reactive coding - RxJava and Spring Reactor, and will show some code samples. It will then bring the audience to the next level of "reactivity' by introducing 2 reactive frameworks - Akka and Vert.x, which are usually used for implementing reactive microservices. It will draw some comparisons between these 2 frameworks and cite some real-life examples of their usages.
The takeaways for the audience will be an understanding of the key differences between reactive programming versus reactive systems, and the strength and weaknesses of each of the surveyed frameworks.
## About the speaker: Mary Grygleski
Mary is currently a Java Developer Advocate for IBM's Digital Business Group, specializing in Reactive Java systems. She has been riding the software tech waves since 1989, starting with Unix and C, then set sail for Java, open source, and web in the new Millennium, and now venturing into reactive, mobile, and the DevOps space. In her previous incarnations, she worked for several technology product companies in the Route 128 Boston Technology Corridor as well the San Francisco Bay Area. She now resides in the Greater Chicago area, and is an Executive Board member and the Director of Meetings for the Chicago Java Users Group (CJUG). Mary continues to be amazed by how software innovations can dramatically transform our lives. She can't wait to see what the next tech wave will be like.